A few months ago I had my rear end completely rebuilt with a new 9 bolt Australian carrier from GM and Yukon 3.73:1 gears. All the bearings from the pinion out to wheels were replaced. The work was performed by a highly reputable shop in my city. The GM additive was used and the correct quality gear oil was used. All parts were broken in properly and inspected by the shop. I was advised going from stock 3.45:1 to 3.73:1 gears maybe a little noisier.

I notice at certain RPM levels a whine noise comes from the rear end. As soon as I shift gears or change the RPM the sound goes away. Does anyone know of any product of procedure to deal with this?

 

All of the 9 bolt 3.70 gears that I have delt with made a little noise at a certain RPM or load. I'd say get louder exhaust or a better sterio.

 

mine had a little whine also, with aftermarket rear suspension add ons made the noise a little louder also

 

Ok I understand. I like your sense of humor.

 

Sorry, sometimes I can't help it.

 

Nope nothing to be sorry about. I meant I really laughed when I read the comment about sterio's and exhaust.

 

what happens is..our torque arms act like tunning forks..it sorta sounds like an airplane going to land right?....normal condition..